ref: 5e81cc48bdb00a3e7ae3334728659b8f014248da
dir: /sys/src/cmd/python/Python/memmove.c/
/* A perhaps slow but I hope correct implementation of memmove */ extern char *memcpy(char *, char *, int); char * memmove(char *dst, char *src, int n) { char *realdst = dst; if (n <= 0) return dst; if (src >= dst+n || dst >= src+n) return memcpy(dst, src, n); if (src > dst) { while (--n >= 0) *dst++ = *src++; } else if (src < dst) { src += n; dst += n; while (--n >= 0) *--dst = *--src; } return realdst; }